MALIGNANT TUMORS II—METASTASES AND EXTENSION
Approximately 60% of vaginal malignancies are secondary to tumors arising elsewhere in the body. The relatively high incidence of secondary lesions is due chieﬂy to the frequent extension of carcinomas of the cervix to the adjacent vaginal epithelium and supporting structures. This may occur with all grades and in all clinical stages, even including the so-called intraepithelial carcinomas. In the usual case, the earliest extension from a primary site on the cervix would be into one of the fornices and, in the absence of lymphatic or more distant spread, this would be classiﬁed as a Stage II carcinoma of the cervix, carrying a much graver prognostic signiﬁcance than a Stage I. By convention, tumors involving the vagina and cervix are classiﬁed as cervical in origin; tumors involving the vulva and vagina are similarly classiﬁed as vulvar in origin.
Carcinoma of the endometrium is likely to implant upon the vaginal epithelium adjacent to the cervical canal; following hysterectomy for this disease, the vaginal vault is one of the most common sites of recurrence. Vulvar carcinomas may grow inward to involve a part or the entire vagina, and it is sometimes difﬁcult to distinguish the point of origin.
The vagina is the most frequent site of metastases from uterine chorionepithelioma, and a speculum view of the dark-purple hemorrhagic growth is often the earliest manifestation of the presence of this disease. The tumor is papillary and friable, and it bleeds easily on contact. Diagnosis is made by biopsy, which may be associated with considerable hemorrhage. A history of recent pregnancy or abortion is of assistance to the pathologist, but the microscopic picture of the lesion is too characteristic to be missed, although some confusion may result from points of similarity with malignant hydatidiform mole. Columns of undifferentiated trophoblastic cells invade the smooth muscle of the vaginal wall. The large hyperchromatic nuclei of these trophoblastic cells are frequently in mitosis. Both Langhans and syncytial layers are present in about equal proportion. In spite of its extreme vascularity, the tumor tends to undergo infection and necrosis in some areas.
Another rare secondary vaginal neoplasm is the hypernephroma, or renal cell carcinoma, which forms a nodular, yellow, tumor mass, ﬁrmly ﬁxed and puckering the overlying epithelium. A biopsy of this lesion shows the unmistakable alveolar arrangement of the large, pale-staining cells. A virtually unique vaginal metastatic malignancy is the case of a carcinoma of the thyroid that metastasized to the rectovaginal septum.
Pigmented vaginal lesions may occur, including nevi and melanoma, which account for 9% of vulvar and 5% of vaginal malignant lesions. Many of these may be metastatic from the vulva or other areas of the lower body. Prognosis and therapy of these lesions is predicated on the site and stage of the originating lesion.
Metastases or extensions from carcinomas of the ovary, bladder, or rectum are found in the vagina either before or after treatment of the primary disease. It would be unlikely that these extensions would provide the ﬁrst indication of disease, but nearly all secondary vaginal neoplasms cause foul leukorrhea and bleeding and, if unchecked, may eventually produce urinary or fecal ﬁstulae. Treatment is aimed at the primary malignancy, but irradiation or local excision of the secondary tumor sometimes offers temporary palliation when vaginal ﬁndings or symptoms prompt intervention. Overall the prognosis is generally poor because, by deﬁnition, the primary tumor source is already advanced. Speciﬁc prognosis is determined by the tumor type, tissue of origin, and stage.